1. Field of the Invention
The present invention generally relates to the field of information retrieval systems, and more specifically, to information retrieval systems for searching libraries having restricted access documents.
2. Description of the Related Art
Information retrieval systems, generally called search engines, are now an essential tool for finding information in large scale, diverse, and growing corpuses such as the World Wide Web. Generally, search engines create an index that relates documents (or “pages”) to the individual words present in each document. A document is retrieved in response to a query containing a number of query terms, typically based on having some number of query terms present in the document.
Libraries have documents from many sources and in many forms, including non-electronic format. Some libraries also provide online access to the underlying documents themselves. Libraries may restrict online user access to documents (here including books, journals, periodicals or other media which have been converted to electronically accessible forms) depending on a relationship between the library and the user. For example, students and faculty may get full online access to a university library's holdings.
Many users start their information seeking process using general search engines to identify a set of documents relevant to their information needs. In some cases, these documents are likely to be included in the online holdings of one or more libraries. However, most conventional search engines do not index the holdings of libraries, and thus do not include documents in such libraries in search results. Even among search engines that can index library holdings, these search engines are generally precluded from providing access to documents within these holdings from the search results provided to the user.